Subbing composition



United States Patent 3,228,770 SUBBING COMPOSITION Gale F. Nadeau and Richard J. Hellmann, Rochester,

N.Y., assignors to Eastman Kodak Company, Rochester, N.Y., a corporation of New Jersey N0 Drawing. Filed Aug. 24, 1960, Ser. No. 51,530 5 Claims. (CI. 96-87) This invention relates to a subbing composition and photographic film subbed therewith. More particularly, this invention relates to a subbing composition especially useful for subbing polyester film wherein the subbed film carries a light-sensitive emulsion over the sub.

It is known in the industry that certain of the more recently developed film materials and bases have surfaces which are difficult to obtain the firm bonding of certain other layers thereto.

For example, polyester surfaces exhibit this problem of not readily receiving all the various layers that it may be desirable to bond to such surfaces. Therefore, it is currently the practice in the industry in the manufacture of such polyester film to apply a thin layer of certain polymeric materials, referred to as a sub, to such surfaces. That is, it is already known that some polymeric compositions may be reasonably satisfactorily bonded to the polyester surfaces. With such polymeric layers thereon, then other layers which present difficulties of bonding directly onto the polyester of the like layers may be applied to such subs.

A class of polymeric coatings which have attained considerable use in the industry as subs are generally known as resin latex undercoats. Such undercoats are specifically illustrated by the terpolymers of vinylidene chloride, alkyl acrylates and dibasic acids. Although such terpolymer coatings are very useful and provide a surface for receiving a number of other coatings, it has been observed from the photographic standpoint that when lightensitive emulsions are applied over such terpolymer subs there is a tendency for higher fog. In further detail, we have observed that photographic emulsions, when coated on supports which carry a terpolymer sub, exhibit a tendency for higher fog than when the same photographic emulsions are coated on other types of supports such as cellulose ester supports which do not have the terpolymer sub.

Therefore, it is believed apparent that the development of procedure whereby such subbed polymeric sheeting may be used for carrying photographic emulsions Without the aforementioned higher fog represents a highly desirable result. After extended investigation, we have found a new sub composition which overcomes or minimizes the aforementioned fogging of photographic emulsions.

This invention has for one object to provide a novel subbing composition. Another object is to provide a subbing composition useful on polyester base. A further object is to provide a composition of the class indicated which may be overcoated with a light-sensitive photographic emulsion yet the subbing composition does not adversely affect the emulsion from the fogging standpoint even though the emulsion is in immediately adjacent contact therewith. Still another object is to provide a new film combination comprised of the polymeric base, the novel sub of the present invention and a light-sensitive emulsion positioned over such sub. Other objects will appear hereinafter.

In the broader aspects of our invention we have found that certain subbing compositions may be improved by the incorporation therein of tertiary alkyl phenols, hydroquinone and the like additives. We have found that such sub layers, may be overcoated with light-sensitive photographic emulsions without the emulsions being adversely "ice affected from the fogging standpoint as caused by the sub layer. The amount of the tertiary alkyl phenols and the like additives incorporated in the polymeric sub may range from 0.2% to 5.0% based on the total weight of the sub.

While we do not wish to be bound by any theory of operation concerning the present invention, the following explanation may constitute an explanation of the functioning of the present invention and aid in a better understanding thereof. Polymers containing halide components exemplified by vinylidene chloride polymers are unstable when exposed to either light or heat or combination exposures. These halide containing materials lose hydrogen chloride under such conditions of exposure. In losing hydrogen chloride, an ethylenic bond is formed in the polymer. Such ethylenic linkages are prone to absorb atmospheric oxygen and therefore will form an intermediate peroxide of varying degrees of stability. Inasmuch as practically all photosensitive silver halide emulsions are sensitive to peroxides, it appears that the aforementioned mechanism is responsible for the high incubation fog observed when photographic emulsions are coated on terpolymer subbed polyester film.

The foregoing mechanism is further supported in part by the observation that known vinylidene chloride stabilizers which depend on hydrogen chloride absorbing mechanisms and when added to the subbing compositions under discussion herein are not effective in controlling the aforementioned incubation fog. However, in contrast thereto in accordance with the present invention we have found that by adding certain antioxidant type of inhibitors that the aforesaid fog is minimized and controlled. In further detail, we have found that additives which will prevent the formation of peroxides will render the subbing compositions relatively nondetrimental as respects fogging to emulsion applied thereover. Typical of these additive materials which may be used in the present invention are tertiary alkyl phenols and hydroquinone.

A further understanding of our invention will be had from a consideration of the following examples illustrating certain preferred embodiments.

Example I In accordance with this example 14.7 wt. percent methyl acrylate, 83.3 wt. percent vinylidene chloride and 2.0 wt. percent itaconic acid were emulsion copolymerized to form an emulsion hydrosol. This hydrosol was divided into several portions. One portion was applied to polyethylene terephthalate film support in the usual manner as an undercoat. The undercoat was followed by a gel sub layer in the usual manner then the support thus treated as just indicated was sensitized with a black-and-white Cine Positive light-sensitive silver halide emulsion.

Samples of this photographic film carrying emulsion prepared as just described developed a relatively high fog level at incubation at F. for 46 weeks. Observations indicated that the degree of fog obtained was directly related to the amount of vinylidene chloride terpolymer present in the subbing undercoat. To additional portions of the same hydrosol were added epoxy and alkyl aryl phosphate stabilizers. These stabilizers have the function of absorbing hydrogen chloride which is formed by the degradation of vinylidene chloride terpolymer. These portions of the hydrosol treated with the phosphite stabilizers were coated onto polyethylene terephthalate filrn, the film further coated with a gel layer and a light-sensitive emulsion applied thereover exactly comparable to the procedure set forth above.

Incubation tests on such film again indicated a high fog level.

A further portion of the same hydrosol was segregated to have incorporated therein a content of a tertiary alkyl phenol in accordance with the present invention. That is, to amount of the hydrosol there was added 1% by weight of the particular tertiary alkyl phenol, para-tertiary butyl phenol. This new hydrosol combination of the present invention was then applied to polyethylene terephthalate film by the same type of procedure as utilized in the runs already referred to. Also, the same gelatin undercoating and the same black-and-white Cine Positive emulsion composition were applied to prepare a film product as above but wherein the subbing undercoat contained a tertiary alkyl additive in accordance with the present invention. Incubation tests of this film product indicated that the fog level was not materially increased and that such fog level was no greater than that encountered in commercial film products wherein the lightsensitive emulsion is carried on a cellulose ester base.

Example 11 A hydrosol made from 14.4 wt. percent acrylonitrile, 82.6 wt. percent vinylidene chloride and 4.0 wt. percent acrylic acid was prepared and tested as indicated in EX- ample I. Incubation tests had a reduction in fog level when the tertiary alkyl was present in the sub undercoat.

Example III Example I was repeated using 1% by weight of hydroquinone. The presence of hydroquinone in the subbing undercoat reduced the incubation fog levels.

Example IV The hydrosol listed in Example I was coated on bisphenol A polycarbonate film support and overcoated with a sub containing:

1.20% gelatin .20% cellulose nitrate .125 acetic acid 5.0% water 50.0% acetone 43.475 methanol This film support was then sensitized with a black-audwhite continuous tone graphic arts light-sensitive silver halide emulsion.

-When the undercoat contained para-tertiary amyl phenol, the incubation fog level of the film was considerably lower than without the phenol.

In addition to the additives illustrated in the above examples, other additives such as the following may be utilized in a comparable manner: Catechol, mono alkyl ethers of hydroquinone, dibutyl-p-cresol, butyl hydroXy anisole, p-amino phenol. However, the preferred additive is para-tertiary butyl phenol.

It is believed apparent from the foregoing that we have provided a new subbing composition which is particularly useful in carrying light-sensitive photographic layers thereover in that our composition does not materially increase the fog level in such light-sensitive compositions.

The invention has been described in detail with particu lar reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. A photographic product comprised of a flexible transparent base, a subcoating on the base consisting essentially of a terpolymer comprised of vinylidene chloride, an alkyl acrylate, and a dibasic acid, an additive from the group consisting of paratertiary butyl phenol, hydroquinone, catechol, mono alkyl ethers of hydroquinone, dibutyl-p-cresol, butyl hydroxy anisole, and p-amino phe nol, in the amount of .2-5% by weight of said subcoating contained therein, and further layers on said subcoating including at least one light-sensitive layer whereby the fogging of said layer is minimized by the aforesaid additive.

2. A product in accordance with claim 1 wherein the terpolymer is essentially comprised of vinylidene chloride, methyl acrylate and itaconic acid.

3. A product in accordance with claim 2 wherein there is a gelatin containing layer between the subcoating and the light-sensitive layer.

4. A photographic product comprised of a polyester base, a subcoating on the base consisting essentially of a terpolymer of vinylidene chloride, methyl acrylate, and itaconic acid and from about 0.2% to 5.0% by weight of the subcoating of para-tertiary butyl phenol, a lightsensitive layer, and a layer containing gelatin disposed between the subcoating and the light-sensitive layer.

5. A photographic product comprised of a polyester base, a subcoating on the base consisting essentially of a terpolymer of vinylidene chloride, methyl acrylate, and itaconic acid and from about 0.2% to 5.0% by weight of the subcoating of hydroquinone, a light-sensitive layer, and a layer containing gelatin disposed between the subcoating and the light-sensitive layer.

References Cited by the Examiner UNITED STATES PATENTS 2,334,470 11/1943 Armstrong 260-45.95 2,407,209 9/ 1946 Swan et a1 9687 X 2,650,208 8/1953 Arey et al. 26045.95 2,675,366 4/1954 Pullman 260-4595 2,698,235 12/1954 Swindells 9687 2,727,016 12/1955 Hankins et al. 26080.5 3,010,838 11/1961 Uber 96-87 X 3,053,661 9/1962 Starck et a1. 9687 NORMAN G. TORCHIN, Primary Examiner.

PHILIP E. MANGAN, Examiner. 

1. A PHOTOGRAPHIC PRODUCT COMPRISED OF A FLEXIBLE TRANSPARENT BASE, A SUBCOATING ON THE BASE CONSISTING ESSENTIALLY OF A TERPOLYMER COMPRISED OF VINYLIDENE CHLORIDE, AN ALKYL ACRYLATE, AND A DIBASIC ACID, AND ADDITIVE FROM THE GROUP CONSISTING OF PARATERTIARY BUTYL PHENOL, HYDROQUINONE, CATECHOL, NONO ALKYL ETHERS OF HYDROQUINONE, DIBUTYL-P-CRESOL, BUTYL HYDROXY ANISOLE, AND P-AMINO PHENOL, IN THE AMOUNT OF .2-5% BY WEIGHT OF SAID SUBCOATING CONTAINED THEREIN, AND FURTHER LAYERS OF SAID SUBCOATING INCLUDING AT LEAST ONE LIGHT-SENSITIVE LAYER WHEREBY THE FOGGING OF SAID LAYER IS MINIMIZED BY THE AFORESAID ADDITIVE. 